1. Field of the Invention
The present invention generally relates to refrigeration or air-conditioning systems which operate over a closed thermodynamic cycle and, more specifically, to refrigeration or air-conditioning systems which utilize the Malone thermodynamic cycle in conjunction with an electromechanical compressor.
2. Description of the Related Art
Most refrigeration and air-conditioning systems currently in operation utilize the Gifford-McMahon thermodynamic cycle wherein phase change (condensation and evaporation) of a recirculating working fluid is utilized as a heat transfer medium. However, temperature restrictions at which the phase change and heat transfer must take place have heretofore limited the choice of working fluids to those classified as either chlorofluorocarbons (CFCs and HCFCs) or hydrofluorocarbons (HFCs). In recent years, severe damage to the environment has been attributed to the release of CFCs and HCFCs into the atmosphere. HFCs, though apparently environmentally safe, have proven to be a relatively expensive alternative. The refrigeration and air- conditioning systems in current use also require mechanical compressors, expanders, and heat exchangers of relatively large volume to handle the phase changes of the working fluid. Thus, allocation of compressor, expander, and heat exchanger space has been a limiting factor in any system design.
The idea to use a medium which is continuously liquid as a working fluid was extensively investigated by John Malone who theorized that an ideal thermodynamic cycle employing an all liquid working fluid (Malone cycle) would have an extremely high efficiency. However, the Malone cycle has not heretofore proven to be commercially viable since in actual practice, its performance has been found to be similar to that obtained using conventional phase change technology. Further investigation of Malone cycle performance demonstrated that nearly half of the total lost inefficiency could be attributed to compressor and expander inefficiency.
The utilization of a working fluid that is continuously in a liquid state (Malone cycle) is known in the art and is exemplified in U.S. Pat. No. 4,353,218 (Wheatley et al.) and U.S. Pat. No. 5,327,745 (Gilmour). It is noted, however, that these patents disclose the employment of mechanical means for providing compression force to the liquid.
U.S. Pat. No. 4,795,318 (Cusack), U.S. Pat. No. 4,842,493 (Nilsson), U.S. Pat. No. 5,215,446 (Takahashi et al.), U.S. Pat. No. 5,525,041 (Deak) and Soviet Union Patents numbers (525,438), (1,222,904), (1,239,420) all disclose electromechanical pumping devices for liquids. Compression of liquid for heat exchange purposes is not contemplated in the instant patents.
U.S. Pat. No. 4,515,534 discloses a electromechanical device for compressing a gas.
None of the above inventions and patents, taken either singularly or in combination, is seen to disclose a refrigeration or air-conditioning system utilizing the Malone cycle thermodynamic system in conjunction with an electromechanical compressor as described and claimed in the instant invention.